The recording studio - Mixer: master section

In this section we find all the controls that modify the overall functions of the mixer:

Master fader:

Master fader

This fader controls the mix bus level, in other words, the level of the main bus stereo. In the figure we can also see the LEDs that each time indicate the signals' levels. For example, during the mixing phase the LEDs on the far right indicate the level of the mixbus' signal, whereas the others show the levels of the groups.

Aux send master:

Aux send master

Within the master section, a master potentiometer is present for each aux send on the mixer's channel. Every aux send master controls the overall level of the aux send bus fed by the aux sends of the single channels. Every auxiliary bus can be put in "solo" mode and thus listened to separately.

Aux return master:

Aux return master

It controls the return level coming from the outside world. When the signal present on one of the aux send masters exits the mixer, it usually (though not always) goes down an external path (maybe getting manipulated by a module) and then re-enters the mixer at the aux return input. The latter's level is controlled by the aforementioned aux return master.

For example, to add reverb to a voice, we're proceed as follows: we'd send a copy of the voice to, for example, aux send 1 , and we'd then regulate its output level with the control aux send master 1. The signal that exits the aux send 1 bus is then routed to the reverb module, whose output (usually stereo) returns to the mixer through the aux return 1 input. From then on it can be routed to other destinations: solo bus, group bus, headphone output 1, headphone output 2. Via the aux return master we are now able to regulate the amount of reverb we wish to add to our mix.

Oscillator:
mixers usually have an oscillator which can generate different kinds of wave forms at various frequencies. This component is extremely handy for calibrating studio equipment. It is also used for generating control tones to be recorded in the first part of a tape, in order to supply a reference-value for recording levels. By indicating the tone (frequency) recorded, and its level (in dB), for example 1 KHz at +4 dBu, by using another piece of equipment's tape, we'll know if it is calibrated exactly like the one that did the recording.

SOLO system control:

Solo master

The SOLO system works in different ways depending on circumstances.

Desctructive SOLO (aka SOLO in-place):
when applied, the mute command is activated on all the other channels. Listening takes place through the mix bus which means that a possible mixdown created on the mix bus gets destroyed.

Non-destructive SOLO:
the channel on which SOLO is activated is routed to another bus called solo bus. Listening takes place through this bus, and therefore a possible mixdown on the mix bus remains unaltered. This kind of SOLO is usually available in two modalities: PFL (pre-fader listen) in which the signal on the SOLO bus is independent from the channel's fader because it is picked up beforehand, and AFL (after-fader listen), whose signal depends on the channel's fader because it is picked up after it.

Talkback:
the talkback master usually consists in a microphone and a switch. The signal picked up by the microphone gets routed towards the recording room to communicate with the musicians (generally through aux send 1 and 2, as we will soon see), or instead, to the recorder where the engineer's work-notes can be recorded.

Talkback master

Master monitor:
controls the listening volume of the monitor path on the the control room's monitors. As we'll see, in large studios we'd find various sets of monitors, allowing different listenings to take place. The switches that activate the required monitors are located in this section.

Monitor bus master

Status console:
changes the status of the whole mixer from recording status to mixing status, and vice versa.